1- Preheat oven to 375. Butter the bottom and sides of a 9 or 10 inch baking pan.

2- Layer in the pan slices of potatoes and rutabagas without too much stacking. Season the layer with salt and pepper, and sprinkle with some of the chopped leeks, chopped garlic, parsley, thyme, and nutmeg. Dot the layer with 1 or 2 TBS of butter, broken into pea-sized pieces. Layer on more potatoes and rutabagas and then sprinkle with the spices, aromatics, and butter again, repeating and ending with a layer of potatoes and rutabagas.

3- Press down on the gratin to compact it a bit. Dot the top with the remaining butter, sprinkle with the cheese, then pour the milk over the whole thing.

4- Cover with aluminum foil and bake for 40 minutes.

5- Uncover, increase the oven temperature to 450, and bake for another 10 minutes. Cut into squares and enjoy.